Terrestrial Energy notifies nuclear regulator of planned 2019 molten salt reactor licensing application

Terrestrial Energy USA announced today it had informed the US Nuclear Regulatory Commission (NRC) of its plans to license a small modular reactor (SMR) in the USA. Terrestrial said it intends to start “pre-application interactions” with the regulator this year and to make its licensing application in late 2019.

The NRC recently published a letter from Terrestrial responding to the agency’s Regulatory Issue Summary (RIS) published on 7 June last year. An RIS is an NRC request for information regarding future nuclear reactor licence filings.

In its letter, dated 18 November 2016, Terrestrial said it plans to submit an application to the NRC for a design certification or a construction permit “no later than October 2019”.

Terrestrial included the status of the design, analyses, testing, licensing, and project planning for its Integral Molten Salt Reactor (IMSR), which is a liquid-fuelled, high-temperature, 400 MWt advanced reactor power plant design

Why is Terrestrial Energy’s Integral Molten Salt Reactor a big deal ?

• A molten salt 7.4 MWth test reactor was operated at Oak Ridge from 1965-1969. So no question about technical feasability
• A conservative first IMSR design should be competitive with established power at about 3 cents per kWh
• Later designs should be able to get lower than 1 cent per kWh
• Design is walk away safe with passive safety systems
• First designs would produce 6 times less nuclear waste and later designs can close the fuel cycle
• Canada can use the first several hundred reactors to directly produce steam to profitably produce oil from the oilsands
• Canada and Terrestrial Energy can thus use the oilsand reactors to profitably climb the learning curve before factory mass production of supersafe, super efficient and disruptively lower cost reactors
• These system could provide 100% of global electricity demand without any emissions

The NRC is developing a specific licensing framework for advanced reactor designs, Terrestrial noted, adding it has “confidence in the capability” of the regulator to review and reach safety, security, and environmental findings on the IMSR design, “in a timely manner”.

Terrestrial Energy CEO Simon Irish said in today’s statement: “This is a very exciting time for the nuclear power industry. We are moving forward with the design and regulatory actions needed to allow the company to bring the IMSR to market in the 2020s. The IMSR’s design choices will result in an advanced reactor that delivers clean, cost-competitive and high-grade industrial heat. This capability can serve the many and varied heat requirements of industry, and as well as those of the electric power sector where the IMSR’s dispatchablity will be greatly prized.”

Terrestrial is examining four sites for its first commercial plant, which include the Idaho National Laboratory (INL) and additional sites east of the Mississippi River.
Terrestrial says the IMSR “extends the applicability of nuclear energy far beyond its current footprint in on-grid electric power markets” and “promises to increase industrial competitiveness and energy security while concurrently driving deep and rapid decarbonization by displacing fossil fuel combustion across a broad industrial front”.

Molten salt reactors use fuel dissolved in a molten fluoride or chloride salt which functions as both the fuel (producing the heat) and the coolant (transporting the heat away and ultimately to the power plant). This means that such a reactor could not suffer from a loss of coolant leading to a meltdown. Terrestrial’s IMSR integrates the primary reactor components, including primary heat exchangers to secondary clean salt circuit, in a sealed and replaceable core vessel. It is designed as a modular reactor for factory fabrication, and could be used for electricity production and industrial process heat generation.

Last year, New York-headquartered Terrestrial Energy USA’s parent, Canada’s Terrestrial Energy Inc, announced its plans to engage with the Canadian Nuclear Safety Commission in a pre-licensing design review, a first step towards an eventual licence application.

Here is information from an October 2016 Terrestrial Energy presentation on their Integral Molten Salt Reactor

Introduction to Terrestrial Energy
• Terrestrial Energy
• Commercializing a SMR for 2020s deployment
– Cost-competitive with fossil fuel combustion
– Ideal for industrial heat and SMR markets
• Technology – next generation Molten Salt Reactor (“MSR”)
• Proprietary MSR design – the Integral Molten Salt Reactor (“IMSR™”)
• High technology readiness
• Conducting basic/preliminary engineering work
– Concludes with construction and licensing of the first commercial IMSR power plant (400 MWth reactor)
• IMSR development and deployment
• Supported by power utility industry and senior executives, industrial companies, environmentalists and the Canadian Government and DOE
• Commenced VDR with Canadian Nuclear Safety Commission (“CNSC”)
– First MSR vendor to commence regulatory process
• Terrestrial Energy is a leading advanced reactor developer in a fast developing cleantech sector

Advantages of Molten Salt Reactors
• Safety
• Enhanced ability for passive decay heat removal
• Inherent Stability from strong negative reactivity coefficients
• Low pressure and no chemical driving force
• Caesium and Iodine stable within the fuel salt
• Reduced Capital Cost
• Inherent safety can simplify entire facility
• Low pressure, high thermal efficiency, superior coolants (smaller pumps, heat exchangers). No complex refuelling mechanisms
• Long Lived Waste Issues
• Ideal system for consuming existing transuranic wastes
• Even MSR-Burners can close fuel cycle and see almost no transuranics going to waste
• Resource Sustainability and Low Fuel Cycle Cost
• Thorium breeders obvious but MSR-Burners also very efficient on uranium use

Terrestrial Energy Integral Molten Salt Reactor
• LEU fueled MSR-Burner design like the 1980 DMSR
• Integrates all primary systems into a sealed reactor Core unit
• 7 year Core unit “Seal and Swap” approach to graphite lifetime
• Shorter lifetime for vessel and HX simplify qualification
• Planned as 400 MWth (~ 192 MWe)
• Alternate salt and new off gas system
• New passive decay heat removal in situ without dump tanks
• Safety at forefront which leads to cost innovation

In-situ Decay heat removal – New Innovation
• Freeze Valve and Dump Tank the “traditional” approach
• Results in unwanted lower penetrations and regulator likely to
assume failure to drain is possible
• IMSR approach has long been in-situ decay heat removal
• Convection and natural circulation brings decay heat to vessel wall
• Radiant transfer to Guard Vessel (Guard=Containment)
• 700 C surface 9x radiant heat compared to 300 C
• From there, water jacket options or PRISM type RVACS
• Reactor Vessel Auxiliary Cooling System

Terrestrial Energy’s new “IRVACS”
• IMSR utilizes a new innovative concept, proving extremely robust
• Basic concept is a closed cycle innovation of RVACS that retains a further barrier to the outside world
• New “Internal” RVACS or IRVACS moves heat by a closed cycle flow of nitrogen to a false roof acting as a large heat exchanger above the structural roof
• “Fails Better” If roof penetrated, outside air improves performance
• Modeling (including 140 million mesh CFD) showing excellent behavior for even most severe accident scenarios of losing all secondary heat transfer

Challenges solves with IMSR
• “Sealed for life” offers enormous regulatory advantages to accelerate development
• Airborne release risk during graphite swap eliminated
• Long cool down time before moving unit
• Material lifetime and corrosion issues greatly eased
• Good fuel economy on Once Through
• Future recycling to “close” fuel cycle and improve fuel economy commercially attractive
• Offers obvious “razor blade” analogy of continuous sales to attract industrial partners